Jan Warnking
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View article: Flexible and transparent microelectrode arrays for simultaneous fMRI and single-spike recording in subcortical networks
Flexible and transparent microelectrode arrays for simultaneous fMRI and single-spike recording in subcortical networks Open
Current techniques of neuroimaging, including electrical devices, are either of low spatiotemporal resolution or invasive, impeding multiscale monitoring of brain activity at both single-cell and network levels. Overcoming this issue is of…
View article: Assessing radiofrequency safety of active implants by measuring induced radiofrequency currents using MRI
Assessing radiofrequency safety of active implants by measuring induced radiofrequency currents using MRI Open
Purpose During MRI in the presence of active wire‐like implants, such as deep brain stimulation leads, there is a risk of thermal lesions in tissues adjacent to implant contacts due to radiofrequency currents induced in the wire. Currently…
View article: Fast MR signal simulations of microvascular and diffusion contributions using histogram‐based approximation and recurrent neural networks
Fast MR signal simulations of microvascular and diffusion contributions using histogram‐based approximation and recurrent neural networks Open
Purpose Accurate MR signal simulation, including microvascular structures and water diffusion, is crucial for MRI techniques like fMRI BOLD modeling and MR vascular Fingerprinting (MRF), which use susceptibility effects on MR signals for t…
View article: “ <scp>MR</scp> Fingerprinting for Imaging Brain Hemodynamics and Oxygenation”
“ <span>MR</span> Fingerprinting for Imaging Brain Hemodynamics and Oxygenation” Open
Over the past decade, several studies have explored the potential of magnetic resonance fingerprinting (MRF) for the quantification of brain hemodynamics, oxygenation, and perfusion. Recent advances in simulation models and reconstruction …
View article: Relaxometry and contrast‐free cerebral microvascular quantification using balanced steady‐state free precession MR fingerprinting
Relaxometry and contrast‐free cerebral microvascular quantification using balanced steady‐state free precession MR fingerprinting Open
Purpose This study proposes a novel, contrast‐free Magnetic Resonance Fingerprinting (MRF) method using balanced Steady‐State Free Precession (bSSFP) sequences for the quantification of cerebral blood volume (CBV), vessel radius (R), and r…
View article: Vasomotion loss precedes impaired cerebrovascular reactivity and microbleeds in cerebral amyloid angiopathy
Vasomotion loss precedes impaired cerebrovascular reactivity and microbleeds in cerebral amyloid angiopathy Open
Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease in which amyloid-β accumulates in vessel walls. CAA is a leading cause of symptomatic lobar intracerebral haemorrhage and an important contributor to age-related cognitiv…
View article: Contrast-free Blood Volume, Microvascular Properties and Relaxometry mapping using bSSFP MR Fingerprinting
Contrast-free Blood Volume, Microvascular Properties and Relaxometry mapping using bSSFP MR Fingerprinting Open
Motivation: Most MR methods for quantifying microvascular properties involve the injection of exogenous contrast agents (CA). Goal(s): We propose an innovative MRI method that simultaneously maps the deoxygenated cerebral blood volume (CBV…
View article: Relaxometry and contrast-free cerebral microvascular quantification using balanced Steady-State Free Precession MR Fingerprinting
Relaxometry and contrast-free cerebral microvascular quantification using balanced Steady-State Free Precession MR Fingerprinting Open
This study proposes a novel, contrast-free Magnetic Resonance Fingerprinting (MRF) method using balanced Steady-State Free Precession (bSSFP) sequences for the quantification of cerebral blood volume (CBV), vessel radius (R), and relaxomet…
View article: Loss of spontaneous vasomotion precedes impaired cerebrovascular reactivity and microbleeds in a mouse model of cerebral amyloid angiopathy
Loss of spontaneous vasomotion precedes impaired cerebrovascular reactivity and microbleeds in a mouse model of cerebral amyloid angiopathy Open
Background Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease in which amyloid-β accumulates in vessel walls. CAA is a leading cause of symptomatic lobar intracerebral hemorrhage and an important contributor to age-relate…
View article: Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington’s disease
Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington’s disease Open
Background Huntington’s disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have …
View article: Ultrathin, flexible and MRI-compatible microelectrode array for chronic single units recording within subcortical layers
Ultrathin, flexible and MRI-compatible microelectrode array for chronic single units recording within subcortical layers Open
Current techniques of neuroimaging, including electrical devices, are either of low spatiotemporal resolution or invasive, impeding multiscale monitoring of brain activity at both single cell and network levels. Overcoming this issue is of…
View article: Enhancing MR vascular Fingerprinting with realistic microvascular geometries
Enhancing MR vascular Fingerprinting with realistic microvascular geometries Open
Magnetic resonance (MR) vascular Fingerprinting proposes to use the MR Fingerprinting framework to quantitatively and simultaneously map several characteristics that emerge from vascular structure much smaller than voxel size. The initial …
View article: Searching for an MR Fingerprinting sequence to measure brain oxygenation without contrast agent
Searching for an MR Fingerprinting sequence to measure brain oxygenation without contrast agent Open
We propose to use numerical simulations and Monte Carlo approaches to test 40 MR fingerprinting sequences for their ability to quantify the BOLD effect and provide maps of baseline blood oxygen saturation without the need for contrast agen…
View article: Enhancing MR vascular Fingerprinting through realistic microvascular geometries
Enhancing MR vascular Fingerprinting through realistic microvascular geometries Open
MR vascular Fingerprinting proposes to use the MR Fingerprinting framework to quantitatively and simultaneously map several microvascular characteristics at a sub-voxel scale. The initial implementation assessed the local blood oxygenation…
View article: Evidence of cerebral hypoperfusion consecutive to ultrasound‐mediated blood‐brain barrier opening in rats
Evidence of cerebral hypoperfusion consecutive to ultrasound‐mediated blood‐brain barrier opening in rats Open
Purpose This work aims to explore the effect of Blood Brain Barrier (BBB) opening using ultrasound combined with microbubbles injection on cerebral blood flow in rats. Methods Two groups of n = 5 rats were included in this study. The first…
View article: Head holder and cranial window design for sequential magnetic resonance imaging and optical imaging in awake mice
Head holder and cranial window design for sequential magnetic resonance imaging and optical imaging in awake mice Open
Medical imaging techniques are widely used in preclinical research as diagnostic tools to detect physiological abnormalities and assess the progression of neurovascular disease in animal models. Despite the wealth of imaging options in mag…
View article: Using 3D realistic blood vessel structures machine learning for MR vascular Fingerprinting
Using 3D realistic blood vessel structures machine learning for MR vascular Fingerprinting Open
International audience
View article: High-resolution relaxometry-based calibrated fMRI in murine brain: Metabolic differences between awake and anesthetized states
High-resolution relaxometry-based calibrated fMRI in murine brain: Metabolic differences between awake and anesthetized states Open
Functional magnetic resonance imaging (fMRI) techniques using the blood-oxygen level-dependent (BOLD) signal have shown great potential as clinical biomarkers of disease. Thus, using these techniques in preclinical rodent models is an urge…
View article: Optimized cervical spinal cord perfusion MRI after traumatic injury in the rat
Optimized cervical spinal cord perfusion MRI after traumatic injury in the rat Open
Despite the potential to guide clinical management of spinal cord injury and disease, noninvasive methods of monitoring perfusion status of the spinal cord clinically remain an unmet need. In this study, we optimized pseudo-continuous arte…
View article: Optimizing signal patterns for MR vascular fingerprinting
Optimizing signal patterns for MR vascular fingerprinting Open
International audience
View article: SAR comparison between CASL and pCASL at high magnetic field and evaluation of the benefit of a dedicated labeling coil
SAR comparison between CASL and pCASL at high magnetic field and evaluation of the benefit of a dedicated labeling coil Open
Purpose To investigate the heating induced by (pseudo)‐continuous arterial spin labeling ((p)CASL) sequences in vivo at 9.4T and to evaluate the benefit of a dedicated labeling coil. Methods Temperature was measured continuously in the bra…
View article: Neurogliovascular dysfunction in a model of repeated traumatic brain injury
Neurogliovascular dysfunction in a model of repeated traumatic brain injury Open
Traumatic brain injury (TBI) research has focused on moderate to severe injuries as their outcomes are significantly worse than those of a mild TBI (mTBI). However, recent epidemiological evidence has indicated that a series of even mild T…
View article: Interpulse phase corrections for unbalanced pseudo‐continuous arterial spin labeling at high magnetic field
Interpulse phase corrections for unbalanced pseudo‐continuous arterial spin labeling at high magnetic field Open
Purpose To evaluate a prescan‐based radiofrequency phase‐correction strategy for unbalanced pseudo‐continuous arterial spin labeling (pCASL) at 9.4 T in vivo and to test its robustness toward suboptimal shim conditions. Methods Label and c…
View article: PyHRF: A Python Library for the Analysis of fMRI Data Based on Local Estimation of the Hemodynamic Response Function
PyHRF: A Python Library for the Analysis of fMRI Data Based on Local Estimation of the Hemodynamic Response Function Open
International audience
View article: Multiparametric Magnetic Resonance Investigation of Brain Adaptations to 6 Days at 4350 m
Multiparametric Magnetic Resonance Investigation of Brain Adaptations to 6 Days at 4350 m Open
These data demonstrate white matter alterations after several days at high altitude when subjects are asymptomatic that may represent the normal brain response to prolonged high altitude exposure.
View article: Impact of tissue T<sub>1</sub>on perfusion measurement with arterial spin labeling
Impact of tissue T<sub>1</sub>on perfusion measurement with arterial spin labeling Open
A low dose of Mn reduces the tissue T1 without modifying CBF. Heterogeneous T1 impacts the ASL estimate of CBF in a region-dependent way. In animals, and when T1 modifications exceed the accuracy with which the tissue T1 can be determined,…